It has become increasingly necessary and desirable in packaging operations to enable the pick-up, transfer and delivery of packaged articles of various shapes and dimensions in the most reliable, precise and high-speed manner. Many types of such devices have been developed, including the utilization of rotary transfer devices having a vacuum system. Generally, the rotary transfer device functions in cooperation with a vacuum source to pickup, hold and place the packaged product during transfer. Typically, vacuum suction cups of the rotary transfer device engage an article at a predetermined location and for a predetermined period, and then, disengage the article after transfer from one location to another. However, due to the many configurations, shapes, and sizes of packaged articles required to be transferred and processed, it has become increasingly difficult for manufacturers to use suitable transfer mechanisms which enable the reliable pickup, transfer, and placement of these articles. Despite the various rotary transfer mechanisms known in the art, shortcomings and limitations still exist. For example, during the transfer of a packaged product, engagement with the package may be incomplete, thus, causing a failure in the subsequent transfer and placement processes. Generally, this type of malfunction results from a loss of vacuum pressure or suction in the entire vacuum system. Loss of suction can be caused by incomplete surface contact between an individual suction cup and the article to be transferred. In general, suction cups are designed such that the internal pressure or inside the suction cup can be lowered by evacuation, and thus, create the negative pressure or lifting force (suction) needed to secure it to the object to be handled. However, because suction cups are often of a lightweight and rather pliable material, e.g., rubber, and the surface of an article can be textured or irregular, gaps may exist between the suction cup and the article which allows ambient atmosphere to leak into the suction cup cavity. Leakage of air into the suction cup cavity depletes the internal vacuum pressure and consequently, limits the lifting force that can be generated. Typically, the leakage of one suction cup affects the vacuum pressure in an entire system, leaving other suction cups without adequate suction and lifting force. Leakage is particularly a problem with irregularly shaped products packaged in flexible packaging materials which has a greater tendency to have textured and uneven surfaces.
Loss of vacuum pressure can also occur when there is internal structural damage to vacuum system components due to repetitive high speed motion of the rotary transfer device. Typically, these components include one or more metallic solder joints, and over time, the solder cracks due to metal fatigue and subsequently, air leaks into the component and results in the loss of vacuum pressure.
Thus, it is an object of the present invention to overcome the shortcomings and limitations of conventional rotary transfer devices or apparatus.
It is also an object of the present invention to provide an article-handling device with the added benefit of a vacuum system which will prevent malfunction during article transfer due to the leakage of air at one or more suction cups.
It is still further an object of the present invention to provide an article-handling device with the added benefit of a means for distributing vacuum pressure independently to at least two tubular suction shafts to prevent the malfunction during article transfer due to the leakage of air at one or more suction cups.
It is also an object of the present invention to provide an article-handling device having the added benefit of a means for distributing vacuum pressure independently to at least two tubular suction shafts with enhanced structural integrity to prevent the malfunction during article transfer due to loss of vacuum pressure.
It is yet another object of the present invention to provide a more reliable and robust article-handling device for packaging machines, particularly, flexible packaging machines.